The power consumption of an HPC system is not only a major concern due to the huge associated operational cost. It also poses high demands on the infrastructure required to operate such a system. The power consumption strongly depends on the executed workload and is influenced by the system hard- and software and its setup. In this paper we analyze the power consumption of a 32-node cluster across a wide range of parallel applications using the SPEC MPI2007 benchmark. By measuring the variations of the power consumed by different hardware nodes and processes of an applications we lay the ground to extrapolate the energy demand of large parallel HPC systems.